The world waits patiently for the "Thanksgiving Vaccine," the first batch of vaccines released for public use in the last quarter of 2020. November remains an important date in the United States to vaccinate a large number of Americans.

Critical Factor: Availability Ahead of Holiday Travel

Colder weather leading into October and November will lead more of us indoors, hampering social distancing and providing new challenges to new social distancing practices in restaurants. Adding insult to injury, Thanksgiving occurring on the third Thursday each November is the busiest time to travel each year.

Inside Shanghai Hongqiao Railway Station.
Photo by K Hsu / Unsplash

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If a domestic manufacturer proves successful before November,  Pfizer's October vaccine  is the likely candidate. When we spoke with the company last month, a representative who confirmed October remains feasible but is contingent on successful aquisition of an Emergency Use Declaration. Should the company meet this goal, 100 million doses would be available ahead of Thanksgiving.
The earliest date we've covered so far comes out of India who claimed they would have a vaccine as early as August 15, less than two weeks from today. Even with the clever yet financially risky overlapping not only of clinical trials but manufacturing, the date is more than ambitious.

In a letter from WHO chief scientist  Soumya Swaminathan to The Hindu  today, the expert’s outlook on the vaccine’s timeline was more subdued, stating, “A realistic (but very optimistic) timeline from the start of Phase-1 to the completion of Phase-3 could be about six to nine months (if all goes exactly according to plan).” Bharat’s announcement of approval for human trials puts its efforts at the start of the process, starting simultaneously in Phase I and II (not an uncommon practice in vaccine development).

There are at least two ways of looking at the "Thanksgiving Vaccine" problem: on one hand, the lack of a vaccine threatens public health if a non-immunized  travels and spreads the virus. On the other hand, vaccine efficacy requires a critical percentage of the population to have taken the immunization and a wait time is required after immunization to demonstrate that efficacy. The eventual vaccines may even require a second dose to be administered at a later time to arrive at optimal benefit.

Photo by Skyler Smith / Unsplash

Having a highly touted vaccine suddenly available, taken, but by too few and too soon just before this critical time can give the public a false sense of security. Worse, a misleading correlation between the vaccine's availability and a rise in cases could support existing anti vaccine misinformation.

Critical Factor: Percent of Population Immunized

This leads us to the next critical factor. Simply put: If a vaccine is available, who will take it? Pfizer alone estimates 100 million doses of their vaccine will be available. That figure is roughly between 1/4 to 1/3 the population of the United States. In recent polls, only 25% of Americans  said they would accept the vaccine at all suggesting the problem may not be one of the availability of vaccines but willingness to take one at all.

History has shown us this misinformation feeds on itself. Consider the following graphic which is a favorite of anti vaccine social media groups:

Is this graph for real? In fact, it is but supports a false conclusion about vaccine efficacy by stripping out the data which does not support an anti vaccine conclusion.

In the early part of the 20th century, indeed a renewed understanding of the measles virus as well as advanced to modern medicine eventually lead to a decline in cases of measles. This offset of large numbers of cases hides a steady remainder of measles cases ranging from 200,000 to 900,000 each year in the U.S. alone. Following the introduction of the vaccine, these numbers diminished to levels near to zero.

Fast forward to today, SARS-CoV-2 was discovered in late 2019 (hence the name "COVID-19"). Considering the above graph spanning sixty five years of measles, how crude the data would be to examine vaccine efficacy less than a year since the virus' first appearance should the vaccine become available in the last quarter of this year.

Despite the United States' top disease expert, Dr. Anthony Fauci testifying before congress he is "cautiously optimistic" about initial vaccine efficacy, a movement fueled by confirmation bias is unlikely to take an initially underwhelming outcome with stride.

Critical Factor: Vaccine Patience

In a recent article by the Washington Post, disease experts urge the public to view the vaccine as potentially effective, but only over years of continued social preventative measures. As Andrew Noymer, an epidemiologist at the University of California Irvine puts it, "The vaccine is going to be a rollout, not a thunderclap."

“If you’re talking about throwing arms around each other, sitting with 67,000 people at a Philadelphia Eagles game, I’d imagine that would take a couple years,” said Paul A. Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia.

For more takes on science and the battle against misinformation, follow Adam Grant on Twitter.